Rotary blade razor



Nov. 30, 1965 R. w. M cARTHY ROTARY BLADE RAZOR 2 Sheets-Sheet 1 R PI Filed Dec. 17, 1962 INVENTOR. R/cHA/eo W. M40 CARTHY 492 H/s Arron/5K9.

Nov. 30, 1965 w MaocARTHY 3,220,108

ROTARY BLADE RAZOR Filed Dec. 17, 1962 2 Sheets-Sheet 2 X o o mmvrozz. R/c/MRD n4 MAC [ART/1') M: ATTORNEYS.

United States Patent 3,220,108 ROTARY BLADE RAZOR Richard W. MacCarthy, 1162 Pome Ave., Sunnyvale, Calif. Filed Dec. 17, 1962, Ser. No. 245,027 4 Claims. (Cl. 3034.2)

The present invention relates to mechanical safety razors, and pertains more particularly to an improvement in rotary blade razors wherein a peripherally sharpened generally disk type blade is rotated continuously in one direction.

In the past, various types of movable blade razors have been developed, which have included vibrating and oscillating blade structures, as well as shearing types, wherein thin shear blades are employed to sever the hairs close to the skin.

An object of the present invention is to provide a rotary blade razor, wherein the axially outward surface of the rotary blade preferably is exposed for contact with the skin, a toothed blade back up ring being mounted in light, resilient contact with the axially inward peripheral portion of the blade, the blade being surrounded, with slight radial clearance, by a skin tautening sleeve, which rides along on the skin in advance of the blade edge, and, in conjunction with the frictional engagement of the skin by the blade, and the action of the toothed blade back up ring tends to erect the hairs or whiskers for close, easy, transverse severing by slicing when engaged by the blade edge.

Another object of the invention is to provide an improved rotary blade razor wherein a rotary razor blade is mounted with an axially inward peripheral portion thereof riding, with light, resilient pressure, on a toothed sleeve, or back-up member, whereby the blade is subjected to a honing action and the hairs to be severed are guided between teeth on the back-up member into severing relation with the cutting edge of the blade.

Another object of the invention is to provide a rotary blade razor having a toothed, blade back-up ring mounted coaxially of the axis of blade rotation, the teeth of the back-up ring being inclined to radii from such common axis in a direction opposite to that of blade rotation, whereby the friction of the blade on the skin of a person during shaving exerts a gentle, frictional action on the skin, tending to draw the skin in a direction to move the hairs thereon radially inwardly into the spaces between the teeth on the back-up ring for slicing, severing engagements of the hairs on the skin by the cutting edge of the blade.

Another object of the invention is to provide an improved, rotary blade razor.

These, and other objects and advantages of the invention, will be apparent from the following description and the accompanying drawings, wherein:

FIG. 1 is a view, partly in side elevation, and partly in longitudinal, medial section, of a rotary blade razor embodying the present invention.

FIG. 2 is a rear, elevational view looking in the direction of the arrows 22 of FIG. 1, portions being broken away, a rear plastic closure member being removed, and

' the outline thereof being indicated by a dash-dot line.

FIG. 3 is a fragmentary, elevational view of the cutting head, looking in the direction of the arrow 33 of FIG. 1, portions being broken away.

an end portion of the spindle being included.

FIG. 6 is an enlarged, fragmentary, end elevational view showing a portion of the toothed sleeve on which a 3,229 8 Patented Nov. 30, 1965 peripheral portion of the blade rides, and includes fragments of the blade and the surrounding skin tautening sleeve.

FIG. 7 is a fragmentary, sectional view taken along line 77 of FIG. 6.

FIG. 8 is a fragmentary, sectional view taken along line 8-8 of FIG. 7.

FIG. 9 is an exploded, perspective view of the housing, including the blade back-up and skin tautening sleeves.

FIG. 10 is a front, elevational view of the housing shell, with the bottom closure member secured therein.

FIG. 11 is a fragmentary elevational view generally similar to FIG. 3, but showing a modified structure employing a thin, throw-away type of blade.

FIG. 12 is a sectional View taken along line 1212 of FIG. 11.

FIG. 13 is an elevational View, similar to FIG. 11, but with the blade removed.

FIG. 14 is a plan view of the outer side of the blade shown in FIGS. 11 and 12.

Briefly, the form of the invention shown in FIGS. 1-10 comprises a rotary blade razor A (FIGS. 1-3) having a housing 10 comprising a shell portion 11, and interfitting plastic and metal portions best shown in FIGS. 1, 9, and 10. A conventional drive motor B, through conventional reduction gearing 12, drives a blade spindle 13 at a suitable slow rate of speed. A disk blade 14 is mounted on the outer end of the spindle 13 for rotation therewith, and is biased axially inwardly to ride gently on the end teeth 15 of a cylindrical sleeve 17. This ring of teeth comprise a back-up means for the blade, and in addition to guiding the hairs against the edge of the blade for severing by slicing they exert a honing action on the blade, and prevent cutting the skin during shaving.

A skin tautening outer sleeve 18 is fitted around a pair of complementary, cylindrically curved spacers 19 and 20 with suificient frictional engagement therewith to retain the sleeve 18 against endwise displacement during shaving, but to permit it to be axially adjusted by grasping it with ones hand.

In using the razor A, the skin tautening outer sleeve 18 is adjusted endwise thereof so as to engage the skin ahead of the cutting edge 21 of the blade 14 with the razor A tilted at a desired angle to bring the cutting edge of the blade closely adjacent the portion of the skin to be shaved. With the motor B energized to rotate the blade 14, the razor is then drawn across the face substantially in the same manner as that used in shaving with a conventional safety razor, or with other types of movable blade razors.

Referring to the drawings in greater detail, the housing shell 11 preferably is of drawn metal, such as brass, and an end closure cap 22, which may be of molded plastic, is secured in one end thereof by screws 23 (FIGS. 1, 2, 9 and 10). The rear side of the other end of the shell 11 is cut away at 24 on a circular curve, as best shown in FIGS. 2, 9 and 10, and a rear closure member 25, having a substantially circular portion 27, and a substantially semi-cylindrical skirt portion 28 formed integrally thereon, is fitted into this cut-out shell portion 24. A rabbeted groove 29 (FIG. 1) is provided around the exposed edge of the circular portion 27 of the rear closure member 25 for fitted inter-engagement with the correspondingly curved edge 24 (FIGS. 9 and 10) of the shell 11.

The integral, semi-cylindrical skirt portion 28 of this rear closure member 25 fits into the cut-out end portion of the shell 11, which has inwardly curved ears 30 and 31, best shown in FIG. 10, which overlie and embrace, and tend to retain therein, the semi-cylindrical skirt portion 28 of the rear closure member 25. To steady the rear closure member 25 against free tilting movement such as, for example, Bakelite.

when assembled with an inner head member 32, a metal tongue 33 (FIGS. 1, 2, 4 and 9), is embedded in the semi-cylindrical skirt portion 28, and extends endwise therefrom. This tongue 33 is curved transversely thereof to conform to, and to fit closely against the inner head member 32 when the latter is mounted on the shell 11 by a pair of mounting screws 34.

The two substantially semi-cylindrical, complementary spacers members 19 and 20 embrace the head member 32, and are attached thereto by pins 39, which are integrally connected to the inner head member 32, and fit into holes provided therefor in the spacers 1s and 20 to anchor the latter against displacement when enclosed within the skin tautening sleeve 18. The spacers 19 and 20, which may be of metal or plastic, have complementary notches 40 and 41 respectively therein to receive the tongue 33 of the rear closure member when the parts are assembled as shown in FIGS. 1, 2 and 4. These spacers 19 and 20 are of an external diameter to allow the skin tautening sleeve 18 to be fitted slidably thereon as shown in FIG. 1, and to have sufficient frictional engagement therewith to retain the sleeve 18 against axial displacement when subjected to the light, endwise pressures exerted thereon during shaving, but to permit axial adjustment of the sleeve 18 by ones grasping it manually.

The inner head member 32, as best shown in FIGS. 1 and 9, preferably is of a hard, durable, plastic material,

It has a truncated, conical depression 42 in its outer end, and also has a bearing hole 43 for the blade spindle 13 extending axially therethrough. The head mounting screws 34 fit freely through holes 44 provided therefor in the shell 11, and are screwed into threaded holes provided therefor in the inner head member 32 to secure the latter to the shell coaxially with the rear closure member 25.

The cylindrical, toothed, blade back-up sleeve 17 is seated snugly in a rabbeted, annular recess 45 (FIG. 1) provided therefor around the axially outward end of the inner head member 32. The annular recess 45 is of the same depth as the thickness of the sleeve .17, so that the latter will be flush with the unrecessed portion of the inner head member.

Referring now to the operative or moving portions of the razor A, the motor B (FIGS. 1 and 2) is a conventional electric motor, although any suitable drive means for rotating the blade 14 at a desired speed during shaving may be substituted therefor. The illustrated motor B is provided with a usual connection for a conventional extension cord 50. I

A spur pinion 51 is mounted on the motor armature shaft 52, and is in mesh with a spur gear 53 on a shaft 54 journaled in a support member 55. A worm pinion 57 is mounted on the gear shaft 54, and is in mesh with a worm gear 58 mounted on the blade spindle 13. The latter is journaled in the axial hole 43 in the inner head member 32, and is retained against axial displacement therein in one direction by the hub of the worm gear 58, which bears against a washer 59 on the inner end of the inner head member 32, and in the other direction by a washer 60, which bears on the truncated bottom of the depression 42 in the outer end of the inner head member 32. The washer 60 is retained against outward displacement by a split washer 62 mounted in a groove provided therefor in the blade spindle 13.

The outer end portion 64 of the blade spindle 13 is of reduced diameter, and is threaded. The comparatively thick blade disk 14 shown in FIGS. 1-8 has a central depression 65 therein, and an axial hole 67 through the bottom of this depression is of a size to fit freely onto the blade spindle 13. A pair of diametrically opposite notches 68 are provided in the side of the hole 67 to receive freely therein the legs 69 of a blade driving washer 70, which preferably is of springy material, such as mild spring steel or spring brass. The washer 70 has a central hole therein of a size to receive freely therein the reduced, threaded end portion 64 of the blade spindle 13. The diameter of the washer preferably is larger than the axial hole 67 in the blade 14, and the free end portions of the washer legs 69 are bent outwardly so as to retain the washer with the blade when the latter is removed from the spindle.

A tapered, helical, blade biasing spring 71 of light spring wire is of an external diameter at its large end to fit into the central blade depression 65 beneath a blade retaining nut 72, and of an internal diameter at its smaller end to fit into a marginal recess 73 provided therefor in the nut 72. The latter is internally threaded to screw onto the reduced, threaded spindle portion 64, and is of an external diameter to fit freely into the central blade depression 65. When screwed onto the spindle to the position shown in FIG. 1, this nut 72 firmly grips the blade driving washer 70 between the nut 72 and the shoulder 76 (FIG. 5) at the inner end of the reduced threaded shaft portion 64. At the same time the nut 72 compresses the spring 71, and thereby lightly biases the blade 14 against the ends of the teeth 15 on the sleeve 17.

Rotation of the blade 14 while subjected to this biasing force causes the blade to seat on the teeth 15 to thereby exert a mild honing action on the blade during use, the free fit of the blade on the spindle, and of the Washer legs 69 in the blade notches 68 permitting the blade to seat on these teeth. This seating of the blade on the teeth 15 during use is also important due to the fact that if the blade does not seat snugly on these teeth during use it is apt to nick the user.

The teeth 15 preferably are formed substantially as shown in the enlarged, detail views of FIGS. 68. Each tooth 15 is narrow circumferentially of its sleeve 17, and preferably is disposed at an angle to a radial plane 75a through the inner end of the tooth. This angle 75 is not critical but it has been found that it may vary at least within the range of 45 to 60' degrees. The direction of this tooth angle 75 is opposite to the direction of blade rotation, which is indicated by the curved arrow in FIG. 6. These teeth also are made with a positive rake of preferably between 15 and 30 degrees as best shown in FIG. 1.

The ends of all of the teeth 15 define a common, flat, circular surface 77 normal to the common axis of the toothed sleeve 17, and of blade rotation. The diameter of this circular tooth-end surface 77 .is equal to or slightly greater than the external diameter of the blade 14, so that the cutting edge 21 of the blade is coincident with or slightly within its periphery. The radially outward portion of each tooth beyond this circular surface 77 is beveled at 78 (FIG. 7).

The skin tautening sleeve 18 is axially adjusted to a position where it is offset axially inwardly from these outer, beveled tooth faces 78 by a distance approximately equal to the radial clearance of the skin-engaging end portion of the skin tautening sleeve 18 from the outer edges of the teeth. By this arrangement, as best seen in FIG. 7, when the cutting edge 21 of the blade is in close, shaving proximity to the skin, an outer surface portion of the blade 14, the beveled outer faces 78 of the teeth 15, and end of the skin tautening sleeve 18 will all engage the skin.

In using the razor A illustrated in FIGS. 1-8 the extension cord 50 is connected to a suitable source of electricity. The blade 14 is assembled on the spindle 13 as shown in FIG. 1, with the blade retaining nut 72 screwed down to grip the blade driving washer 70, and to com press the light helical spring 71 into suitable biasing engagement with the blade 14 to cause the latter to bear lightly and uniformly on the fiat end faces of the teeth 15. The skin tautening sleeve 18 is then axially adjusted to a desired position to suit the individual using it. A suitable position is with the outer, skin engaging end of the sleeve 18 set back from the outer edges of the teeth 15 by a distance substantially equal to its radial clearance from the teeth.

The razor A is now ready to use, and upon energizing the motor B by means of a usual electric switch (not shown) to rotate the blade 14, the razor is pressed gently against the skin at an angle which will bring the cutting edge 21 of the blade 14 closely adjacent the skin. The razor is then drawn along the skin in strokes comparable to those used, for example, when shaving with a conventional safety razor.

A modified form C of the invention is shown in FIGS. 11-14. Only the portions of the form C in the zone of the blade are illustrated. The remainder of this form of the invention is assumed to be similar to the form A of the invention shown in FIGS. 1-8. Some of the parts shown in FIGS. 11-14 are also substantially similar to corresponding parts of the form A of the invention shown in FIGS. l-S, and such parts are identified by the same reference numerals used in FIGS. 1-8 with the suffix a added. The toothed end sleeve 17 may be omitted, and a thin disk blade 80 is employed. This blade 80 is of a thickness comparable to the well-known, thin, doubleedge type of safety razor blade. The blade 80 is intended to be used only as long as it remains sharp, after which it is discarded and replaced by a new blade of the same type.

To support the blade 80, a blade support disk 81, which may be of hard plastic or other non-magnetic material, is fixedly secured coaxially onto a reduced, unthreaded, end portion 64a of a blade spindle 13a. The reduced end portion 64a of the spindle projects beyond the disk 81 a distance approximately equal to the thickness of the blade 80, which has a central hole 85 therein of a size to fit snugly onto the projecting portion of the spindle as shown in FIG. 13. A pair of bar magnets 84 are embedded in the blade support disk 81, and are of sufficient strength to retain the blade 80 fiat against the outer face of its support disk 81.

A large headed, blade retaining pin 87, of magnetically permeable material such as steel, has the shank portion 88 thereof of a diameter to fit freely into an axial hole provided therefor in the end of the spindle 13a. The pin 87 is mounted with the large head portion 89 thereof within the magnetic fields of the magnets 84. The magnets thus magnetically attract the large head 89 of the pin as well as the blade 80 to hold the latter snugly against the face of the disk 81.

A skin tautening sleeve 18a is of an internal diameter just slightly greater than the external diameter of the blade 80, for example, of the order of .020" greater, so that the radial clearance between the cutting edge 21a of the blade 80, and the end of the skin tautening sleeve 18a is of the order of .010". The exposed, skin engaging end annulus of the skin tautening sleeve 18a is plain, or untoothed, and this type of plain or untoothed skin tautening sleeve may be used in either the form A of the invention shown in FIGS. 18, or that shown in FIGS. 11-14. At the present time no particular advantage has been found to reside in either the toothed or untoothed form of skin tautening sleeve, and both have been found to work satisfactorily.

A very important advantage of the form C of the invention shown in FIGS. 11-14 resides in the fact that in the event that one should desire to use it under conditions wherein the blade could not be rotatively driven, i.e. in case of motor failure or lack of available electricity, the razor C works very satisfactorily as a stationary blade safety razor. In fact, due to its circular shape, it fits into some contours of the face and neck much better than a straight edged razor, either stationary blade or electric. Furthermore, it may be drawn along the skin in any direction upon tilting the razor to bring the cutting edge of the blade into proper contact with the skin as described previously herein.

When thus used as a stationary blade razor, it is, of course, desirable to use lather or shaving cream. An additional advantage inherent in the disk blade of the present invention is the extreme length of the cutting edge, which with a blade of one inch diameter, would be over three and one-eighth inches. From the foregoing it is obvious that the form C of the invention has many desirable features, even when used with non-rotating blade razor.

The present invention provides a simple, rugged, and very effective shaving instrument. In the form A of the invention shown in FIGS. 1-8, due to the constant honing action to which the blade 14 is subjected during use, the latter will retain its keen cutting edge almost indefinitely unless nicked or damaged. The form of the invention shown in FIGS. 11-14 is also strong and durable, and due to the slicing action achieved by the rotation of the blade, and the skin tautening effect caused by frictional engagement with ones skin of the skin tautening sleeve 18a and the blade 80, the latter will continue to shave satisfactorily even when the edge thereof is considerably less sharp than is required for satisfactory shaving with a razor of either the safety or straight edge type.

While I have illustrated and described a preferred embodiment of the present invention, and one modified form thereof, it will be understood, however, that various changes and modifications may be made in the details thereof Without departing from the scope of the invention as set forth in the appended claims.

Having thus described the invention, what I claim as new and desire to protect by Letters Patent is defined in the following claims:

1. A rotary blade razor comprising,

a housing,

a rotary spindle journaled in said housing,

a disk blade having a sharpened peripheral slicing edge mounted coaxially on the spindle for rotation therewith,

a sleeve mounted coaxially of the blade on the support,

a plurality of endwise extending teeth on the sleeve,

the end surfaces of the teeth defining a common surface corresponding to the axially inward surface of the peripheral portion of the blade and extending radially to its slicing edge, each of the teeth being inclined at an acute angle to the radius from the spindle axis through the tooth in a direction opposite to that of blade rotation to draw whiskers entering the spaces between the teeth into slicing relation with the cutting edge of the blade,

means lightly biasing the blade and sleeve axially toward each other to urge the ends of the teeth into light, frictional, honing engagement with the corresponding peripheral portion of the blade,

each tooth extending radially beyond the periphery of the blade,

means for rotating the spindle and the blade thereon relative to the teeth, and

a skin engaging annular member mounted on the support coaxially of, and spaced radially outwardly a slight distance from the sharpened peripheral edge of the blade,

said annular member being axially adjustable to a position just axially inwardly of the blade edge,

whereby, when the razor is applied to the face of a user with a portion of the axially outward face of the blade extending to the peripheral slicing edge thereof and the annular skin engaging member in contact with the skin of the user, and is drawn in such position across a whiskered area of a users face with the blade rotating, the whiskers on such area will be severed by slicing by the blade edge.

2. An arrangement according to claim 1 wherein each of the teeth is also formed with a positive endwise rake relative to the direction of blade rotation.

3. A rotary blade razor comprising,

a rotary spindle,

a disk blade having a sharpened, peripheral slicing edge mounted coaxially on the spindle for rotation there'- with,

a circular row of narrow teeth, substantially coaxial with the blade, the teeth being spaced slightly apart circumferentially of the circle thereof, their axially outer ends defining a common circular surface of a diameter substantially equal to that of the blade, and shaped to conform to an axially inward, marginal portion of the blade,

a portion of each tooth extending radially beyond such common circular surface and with its axially outward end inclined to slope axially inwardly to support the skin of a user clear of the peripheral edge of the blade,

means urging the conformingly shaped portions of the blade and teeth into light frictional engagement with each other, and

means for slowly rotating the spindle and the blade thereon relative to the circular row of teeth,

whereby, when the razor is applied to a whiskered skin area of a user with a marginal portion of the axially outward face of the blade extending to the peripheral slicing edge thereof in contact with such skin, and is drawn, cutting edge forward, in such position over such skin with the blade rotating, the whiskers in the inter-tooth zones of such skin area will be severed at the skin by slicing engagement by the blade edge.

4. A rotary blade razor comprising,

a rotary blade support,

a disk blade having a sharpened peripheral slicing edge mounted coaxially on the blade support for rotation therewith, the axially outward side of the blade being exposed for frictional contact with the skin of a user,

a circular row of narrow teeth spaced slightly apart circumferentially of the row thereof, and with a surface of each tooth conforming to, and lightly contacting a peripheral marginal portion of the axially inward side of the blade and extending in contact therewith to the slicing edge of the blade, a portion of each tooth extending radially outwardly beyond the blade, the axially outward end of the radially outwardly extending portion of each tooth sloping axially inwardly away from the plane defined by the blade edge, and means for slowly rotating the blade support and the blade thereon relative to the row of teeth, whereby, when the razor is applied to a whiskered skin area with a portion of the axially outward face of the blade extending to the peripheral cutting edge thereof in contact with such skin, and is drawn, cutting edge forward, in such position across such skin area with the blade rotating, whiskers encountered by inter-tooth portions of the blade edge will be severed at the skin by slicing, and frictional engagement of the outward side of the blade tends to move the skin engaged thereby transversely of such blade edge.

References Cited by the Examiner UNITED STATES PATENTS 1,351,507 8/1920 Collins 3042 1,416,199 5/1922 Hasselquist 3042 2,149,403 3/1939 Muros 3043.3 2,166,025 7/1939 Schwarz 3043 2,166,035 7/1939 Aronson 3043 2,229,959 1/1941 Dalkowitz 30-43 2,265,305 12/1941 Nyhagen 30-43 2,281,531 4/1942 Casner 30-43.4 2,808,645 10/1957 Tournier 30-43 FOREIGN PATENTS 295,986 1/ 1917 Germany.

WILLIAM FELDMAN, Primary Examiner.

EDWARD V. BENHAM, Examiner. 

1. A ROTARY BLADE RAZOR COMPRISING, A HOUSING, A ROTARY SPINDLE JOURNALED IN SAID HOUSING, A DISK BLADE HAVING A SHARPENED PERIPHERAL SLICING EDGE MOUNTED COAXIALLY ON THE SPINDLE FOR ROTATION THEREWITH, A SLEEVE MOUNTED COAXIALLY OF THE BLADE ON THE SUPPORT, A PLURALITY OF ENDWISE EXTENDING TEETH ON THE SLEEVE, THE END SURFACES OF THE TEETH DEFINING A COMMON SURFACE CORRESPONDING TO THE AXIALLY INWARD SURFACE OF THE PERIPHERAL PORTION OF THE BLADE AND EXTENDING RADIALLY TO ITS SLICING EDGE, EACH OF THE TEETH BEING INCLINED AT AN ACUTE ANGLE TO THE RADIUS FROM THE SPINDLE AXIS THROUGH THE TOOTH IN A DIRECTION OPPOSITE TO THAT OF BLADE ROTATION TO DRAW WHISKERS ENTERING THE SPACES BETWEEN THE TEETH INTO SLICING RELATION WITH THE CUTTING EDGE OF THE BLADE, MEANS LIGHTLY BIASING THE BLADE AND SLEEVE AXIALLY TOWARD EACH OTHER TO URGE THE ENDS OF THE TEETH INTO LIGHT, FRICTIONAL, HONING ENGAGEMENT WITH THE CORRESPONDING PERIPHERAL PORTION OF THE BLADE, EACH TOOTH EXTENDING RADIALLY BEYOND THE PERIPHERY OF THE BLADE, MEANS FOR ROTATING THE SPINDLE AND THE BLADE THEREON RELATIVE TO THE TEETH, AND A SKIN ENGAGING ANNULAR MEMBER MOUNTED ON THE SUPPORT COAXIALLY OF, AND SPACED RADIALLY OUTWARDLY A SLIGHT DISTANCE FROM THE SHARPENED PERIPHERAL EDGE OF THE BLADE, SAID ANNULAR MEMBER BEING AXIALLY ADJUSTBLE TO A POSITION JUST AXIALLY INWARDLY OF THE BLADE EDGE, WHEREBY, WHEN THE RAZOR IS APPLIED TO THE FACE OF A USER WITH A PORTION OF THE AXIALLY OUTWARD FACE OF THE BLADE EXTENDING TO THE PERIPHERAL SLICING EDGE THEREOF AND THE ANNULAR SKIN ENGAGING MEMBER IN CONTACT WITH THE SKIN OF THE USER, AND IS DRAWN IN SUCH POSITION ACROSS A WHISKERED AREA OF A USER''S FACE WITH THE BLADE ROTATING, THE WHISKERS ON SUCH AREA WILL BE SEVERED BY SLICING BY THE BLADE EDGE. 